Effects of successive-stage Transient Liquid Phase (S-TLP) on microstructure and mechanical properties of Al2024 to Ti-6Al-4V joint

Al2024 and Ti-6Al-4V alloy were joined by diffusion bonding in two successive stages. In first stage, Transient Liquid Phase of two dissimilar aerospace alloys, Ti-6Al-4V and Ti-6Al-4V welded at 620 °C using 50 µm thick Sn-5.3Ag-4.2Bi interlayer under argon by Transient Liquid phase method. In second stage, Al2024 was welded to Ti-6Al-4V at 453 °C by 50 µm thick Sn-5.3Ag-4.2Bi interlayer. Welded joints were observed and examined using optical, SEM, XRD and mapping Element showing, formation of Ag3Al, Ag2Al, and Al3Ti inter-metallic phases and Sn as solid solution bonding. Bi homogenized in two base metals. Welding tensile strength of Al2024 to Ti-6Al-4V is 62 MPa.